KLINEFELTER'S SYNDROME

Characteristics/ Phenotype

Klinefelter syndrome is a disorder that affects only males. Males normally have an X chromosome and a Y chromosome (XY). But males who have Klinefelter syndrome have an extra X chromosome (XXY), giving them a total of 47 instead of the normal 46 chromosomes. The syndrome can affect different stages of physical, language and social development.

Not all males with the condition have the same symptoms or to the same degree. Symptoms depend on how many XXY cells a man has, how muchtestosterone is in his body, and his age when the condition is diagnosed.

As babies, many XXY males have weak muscles and reduced strength. They may sit up, crawl, and walk later than other infants. After about age four, XXY males tend to be taller and may have less muscle control and coordination than other boys their age.

As XXY males enter puberty, Klinefelter syndrome patients are often tall and usually don't develop secondary sex characteristics, such as facial hair or underarm and pubic hair. Due to extra X chromosomes, it adversely affects testicular growth, and this can result in smaller than normal testicles. This leads to lower production of the sex hormone testosterone. Klinefelter syndrome also cause reduced muscle mass, reduced body hair, and enlarged breast tissue.

Some affected individuals also have genital differences including undescended testes (cryptorchidism), the opening of the urethra on the underside of the penis (hypospadias), or an unusually small penis (micropenis).

By adulthood, XXY males look similar to males without the condition, although they are often taller. They are also more likely than other men to have certain health problems, such as autoimmune disorders, breast cancer, vein diseases,osteoporosis, and tooth decay.

XXY males can have normal sex lives, but they usually make little or no sperm. Between 95 percent and 99 percent of XXY males are infertile because their bodies don't make a lot of sperm.

Many people with this disorder have no idea they have it until they hit puberty or try to have children.  When men with Klinefelter syndrome try to have children, most discover that they are sterile because they cannot produce sperm. Learning disabilities (not categorized as mental retardation) are also a common problem for them. Patients may have trouble using language to express themselves. They tend to be quiet, sensitive, unassertive and have trouble fitting in, but personality characteristics vary among affected individuals.

Some people with features of Klinefelter syndrome have more than one extra sex chromosome in each cell (for example, 48,XXXY or 49,XXXXY). These conditions, which are often called variants of Klinefelter syndrome, tend to cause more severe signs and symptoms than classic Klinefelter syndrome. In addition to affecting male sexual development, variants of Klinefelter syndrome are associated with intellectual disability, distinctive facial features, skeletal abnormalities, poor coordination, and severe problems with speech. As the number of extra sex chromosomes increases, so does the risk of these health problems.

Some people with features of Klinefelter syndrome have the extra X chromosome in only some of their cells; in these individuals, the condition is described as mosaic Klinefelter syndrome (46,XY/47,XXY). Individuals with mosaic Klinefelter syndrome may have milder signs and symptoms, depending on how many cells have an additional X chromosome.

Frequency
Klinefelter syndrome affects 1 in 500 to 1,000 newborn males. Most variants of Klinefelter syndrome are much rarer, occurring in 1 in 50,000 or fewer newborns.

Diagnosis

(47, XXY)

 The only way to confirm the presence of an extra chromosome is by a karyotype test. A health care provider will take a small blood or skin sample and send it to a laboratory, where a technician inspects the cells under a microscope to find the extra chromosome. A karyotype test shows the same results at any time in a person's life.

A pregnant woman may also undergoe chorionic villus sampling or amniocentesis These types of prenatal testing carry a small risk for miscarriage and are not routinely conducted unless the woman has a family history of chromosomal disorders, has other medical problems, or is above 35 years of age.

Cause/s

Klinefelter syndrome and its variants are not inherited; these chromosomal changes usually occur as random events during the formation of reproductive cells (eggs and sperm) in a parent.

Mosaic 46,XY/47,XXY is also not inherited. It occurs as a random event during cell division early in fetal development. As a result, some of the body's cells have one X chromosome and one Y chromosome (46,XY), and other cells have an extra copy of the X chromosome (47,XXY).

Treatments
It is important to start treatment as early as possible. With treatment, most boys grow up to have normal sex lives, successful careers and normal social relationships. Treatments include: Educational services, Physical, speech and occupational therapy, Medical treatments including testosterone replacement therapy which is the best way to treat this disorder. Teenagers are typically given testosterone injections to replace the hormone that would normally be produced by the testes. Synthetic testosterone works like natural testosterone - it builds muscle and increases hair growth.

Recommendations/Advices

If you’re a parent, let your baby undergo diagnostic test to know if he has Klinefelter or none, if he is positive, the best that you can do is to support and give all the attention and care that the child needs.

Never stop guiding your child as he grows up and always be updated of his activities. Monitor his affliations with various people.

References

http://www.medicinenet.com/klinefelter_syndrome/discussion-818.htm

http://ghr.nlm.nih.gov/condition/klinefelter-syndrome

http://learn.genetics.utah.edu/content/disorders/whataregd/klinefelter/

http://www.nichd.nih.gov/health/topics/klinefelter/conditioninfo/Pages/diagnosed.aspx

http://www.nichd.nih.gov/health/topics/klinefelter/conditioninfo/Pages/treatments.aspx

http://www.mayoclinic.com/health/klinefelter-syndrome/DS01057

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